KnowMo
Using the Sine Rule to Calculate the Area of Triangles and Quadrilaterals
The video is a lecture presentation on how to calculate the area of triangles using the A=0.5abSinc formula. The presenter explains what areas are and how they are calculated, and then proceeds to show how to use the formula when one of...
Brian McLogan
Area and Perimeter of Triangle in Coordinate Plane
Timestamps: 0:00 Intro 2:46 Find the Perimeter 6:10 Find the Area Corrections: 4:02 Coordinate Point should be (2,3) Answer is correct as graphed 4:48 Coordinate Point should be (2,3) Answer is correct as graphed
Curated Video
Competition Math Shortcut: Solve For This Special Triangle's Area In Seconds
The leg of a right triangle is equal to 1/5 the sum of the other sides. The triangle has a perimeter of 1. What is its area? My blog post for this video http://wp.me/p6aMk-52p Source: I received a similar problem, from a New York...
Curated Video
This Is Not Impossible! Solve For The Triangle's Area
This is a delightful problem. Find the area of the triangle defined by the four squares. It seems impossible but it can be solved with the right perspective. Can you figure it out? Sources Puzzle by Catriona Shearer...
Curated Video
Evil Geometry Problem
A geometry textbook has the following problem: "A right triangle has a hypotenuse equal to 10 and an altitude to the hypotenuse equal to 6. What is the area of the triangle?" Can you figure out the correct answer? Blog post (text/image...
Curated Video
HARD Geometry Problem: Can You Solve The Horse Grazing Puzzle?
A horse is tied to an outside corner of a 20 foot by 10 foot rectangular barn. What is the maximum area the horse can graze outside, if the rope has length L? Solve for L = 5 and L = 25 (find exact answers). If you are up for a...
Curated Video
How to Make a Simple Pinball Machine with Cardboard
wanted to share a little bit of these analogue holiday memories with you, and I came up with a make-shift pinball machine. MATERIALS: - Cardboard - Wooden clothespin - Wooden popsicle stick - Coloured paper - Plastic or rubber ball -...
Curated Video
A Chinese 5th Grader Solved This In Just 1 Minute! HARD Geometry Problem
Thanks to Bill from New York for this suggestion! Bill emailed me a problem asked to 5th graders in China to identify talented students. A few very talented students did solve it in less than one minute! I was not able to solve the...
CK-12 Foundation
Area and Perimeter of Rhombuses and Kites: Lesson
Flip the triangles up and create a parallelogram. Using the idea of transformations, the video develops the area formula for rhombi and kites. The segment of an extensive geometry playlist uses the formula to find the areas of different...
Mathed Up!
Area of Compound Shapes
Scholars learn how to determine the area of compound shapes by finding the areas of the basic shapes that make it up. Pupils find the areas by adding areas together or subtracting them.
Mathed Up!
Enlargements
Make enlargements with and without centers. Pupils work through seven problems dealing with dilations or enlargements. The first couple items are strict enlargements without centers, while the others have centers. Class members also...
Brightstorm
Finding the Slope of a Line from a Graph - Concept
Explain how to find the slope of a graph of a line with a video that points out how no matter what two points are used on a graph of a line, the slope is the same. A few examples reiterate how to find the slope of vertical...